学习MySQL时遇到一道题，不知道怎么做，求助

[三 四]

[一毛钱的年代]

```
select
b.shipper 快递名称,
a.到付次数,a.现付次数,a.寄付次数
from (select
shipperCode ,
count(1) 使用次数,
sum(case when payment = 0 then 1 else 0 end) 到付次数,
sum(case when payment = 1 then 1 else 0 end) 现付次数,
sum(case when payment = 2 then 1 else 0 end) 寄付次数
from D_order
where userID= '张三'
group by shipperCode
) as a
inner join D_shipper b on a.shipperCode = b.shipperCode

```sql

请参考，如果觉得有帮助，请随意打赏，谢谢